Louis de boux



UNITED STATES PATENT OFFICE,

LOUIS DE ROUX, OF BEGLES, NEAR BOBDEAUX, FRANCE.

METHOD OF PRODUClNG PHOTO-MECHANICAL PRINTING-PLATES.

SPECIFICATION forming part of Letters Patent No. 322,046, dated July 14,1885.

Application filed May 12, 1884. (No specimens.)

- .(0 ject is first taken in the camera in the usual manner. A sheet ofcarbon paper is then exposed to the light under this negative, havingfirstbeen submitted to a bath containing a two per-cent. solution ofbichromate of potassium and dried. After the exposure the carbon sheetis attached to a copper plate which serves as a support or backing.submitted to the action of hot water, whereby the photographic image isdeveloped. The plate bearing the developed image is then pressed upon acomposition of metalin a state of fusion, said composition being formedof the following ingredients, to wit:

Mercury 100 grams. Lead 80 Tin 120 Darcet 700 Magnesia 50 Thiscomposition, which is fusible at a low It is then,

temperature, is melted and poured into any convenient receptacle, andafter having become sufficiently cooled, but while it is still in aliquid state and capable of receiving an impression, the plate bearingthe image, developed as above described, is pressed upon the surface ofthe metallic composition,where it is retained until the metal has becomecold. Upon the removal of the copper plate with the carbon paperattached the photographic image will be found impressed upon the surfaceof the metal, and from this the subject can be reproduced by theordinary process of mechanical printing.

Having thus fully described my invention, what I desire to claim, andsecure by Letters Patent, is-

The herein-described method of producing a photo-mechanicalprinting-plate which consists in forming a composition of mercury, lead,tin, darcet, and magnesia in or about the proportion specified, thenimpressing a plate bearing a photographic image in relief upon thesurface of the composition while it is in a liquid and impressiblestate, substantially as described.

LOUIS on some Witnesses:

A. DE RoUX, GREGORY PHELAN.

